Chemistry Practicals
Chemistry Practicals from Home Education. Many of the practicals recommended in the syllabus can be carried out at home; it is surprising how much can be done with relatively little kit, but you may also find that equipment is often affordable. For those experiments which you are not able to carry out at home, there are videos on YouTube. Many school chemistry classes use videos rather than hands-on practicals for a reasonable proportion of the syllabus. Some options for gaining practical experience: *Work through some of the experiments in the syllabus yourself. Practical suggestions on how to do it further down this page. *Find a local chemistry tutor and ask them to carry out some experiments with you. We did this for practicals that I was not confident about, and it worked well. The tutor would give me shopping lists of chemicals to obtain and worked with what equipment we had or could obtain cheaply and easily. He enjoyed the chance to do real chemistry rather than helping kids cram! *Some tutorial colleges and Further Education colleges offer practical science courses, although these are most often aimed at A-level students - eg http://www.campbellharris.co.uk/Content.asp?ID=67 Campbell Harris A-level Chemistry evening course *Chemistry Camps and Roadshows run by universities etc, eg http://saltersinstitute.co.uk/camps/camp-news/ Salters Chemistry Camps have been very highly recommended by home-ed families. See below. *Royal Institution's Young Scientist Centre workshops, and other similar activities at science museums. Salters Chemistry Camps Salters Chemistry Camps] "Students spend three days and two nights at the Host University, staying in the University Halls of Residence, and using the laboratories. They carry out new, exciting experiments, and have the chance to delve into areas of chemistry that are perhaps not covered at school. Further background information is presented through entertaining lectures and (often noisy!) demonstrations. In the evenings, practical work in the labs is put on the back burner, and students enjoy a variety of social activities." Home-ed parents can nominate children in the same way that schools can, and several home-ed children have highly recommended these camps in the past. Students should be in Year 10, ie aged 14-15; not sure if there is any flexibility on this. Also do Salters Festival of Chemistry for younger children. Royal Institution Young Scientist Centre Institution L'Oreal Young Scientist Centre in London, has workshops which involve practical lab work for different age groups. London home-ed groups regularly organise school sessions there, but you can also book as individuals during their Summer School, for instance. Supplies You can get most chemicals and equipment you need for IGCSE level, in small quantities, on eBay. Kitchen Chemistry on eBay sells small quantities of chemistry kit spares. See also the following suppliers of equipment and/or chemicals which have been recommended by home educators: *Rapidonline *Betterequipped.co.uk *Edulab Mel Science has a subscription scheme with chemistry supplies. It's aimed at ages 9-14 so below IGCSE level, but has been recommended by some home educators as good preparation. Suggested Practicals From the Edexcel IGCSE Chemistry Teacher's Guide. Principles of Chemistry *Diffusion of gases and in solutions • *Diffusion of NH3(g) and HCl(g) • *Physical properties of substances compared to structure and bonding • *Determination the formula of copper oxide by reduction • *Determination of the volume of one mole of hydrogen • *Acid/alkali titrations • *Electrolysis of molten lead bromide • *Electrolysis of aqueous solutions Chemistry of the Elements *Determination of the oxygen content of the air • *Laboratory preparation of oxygen • *Burning elements in oxygen • *Laboratory preparation of carbon dioxide • *The thermal decomposition of copper(II) carbonate • *Group 1 metals with water . You can sometimes buy small quantities of Group 1 metals on eBay. *Displacement reactions of metals (solutions and thermite type) - Copper Sulphate displacement reactions are easy and fun. *Reduction of metal oxides using carbon • *Cause and prevention of rusting • Anion and cation analysis • *Reaction of halogens with iron wo *ol/‘Dutch metal’ • *Dissolving hydrogen chloride in water and methylbenzene • *Endothermic reactions – sodium carbonate decahydrate with citric acid crystals • *Measurement of enthalpy change (displacement reactions; combustion) Organic Chemistry *Fractional distillation of ‘artificial crude oil’ • *Reaction of hexane with bromine in uv light • *Reaction of alkenes with bromine water • *Dehydration of ethanol Physical Chemistry • *The effect of acids and alkalis on a selection of indicators • *Reactions of acids with metals, metal carbonate and metal oxides • *Making crystals of a soluble salt using an insoluble metal oxide or metal carbonate • *Making crystals of a soluble salt by titration • *Precipitation reactions • *Making dry samples of insoluble salts • *The effect of heat on ammonium chloride • *The effect of surface area on rate using marble chips and hydrochloric acid • *The effect of concentration on rate (metals/marble chips with acid; thiosulfate with acid; clock reactions) • *The effect of temperature on rate (metals/marble chips with acid; sodium thiosulfate with acid; clock reactions) • *Catalytic decomposition of hydrogen peroxide Chemistry in Society *Making polystyrene • *Cracking long chain alkanes • *Nylon rope trick. Heating curve for water: definitely do-able at home! Tips from practicalphysics may help: http://www.practicalphysics.org/go/Experiment_207.html and here: http://www.kentchemistry.com/links/Matter/HeatingCurve.htm Nylon Rope Trick- synthesising nylon. Can be done at home with care, using this Nylon Rope Trick kit from Edulab Safety Safety is your responsibility. Please don't attempt a practical activity unless you are confident. If you are worried about this, you could consider asking a chemistry tutor to do some practical activities with your children. Learn Chemistry -The Royal Society of Chemistry Detailed instructions on how to conduct many practical activities. These include safety advice. They work with Nuffield Practical Science, so you will find the same resources on both sites. CLEAPSS is the organisation which advises schools on safety in science practicals. They produce guidance on many activities, and 'hazcards' which advise on safe use of the substances involved. Although some of the material is behind a paywall, you can usually find it online - see the links below. Student Safety Sheets - A free resource giving hazard and risk information on common laboratory chemicals and processes for use by pupils. Most or all classic chemistry practicals can be found on YouTube. It can be helpful to watch several different videos before attempting an activity yourself, so you know what to expect, and to pick up tips from the demonstrators. If you are not confident carrying out the activity yourself then just watch the video. Microscale Chemistry Microscale chemistry experiments use small quantities of chemicals and simple equipment. This reduces costs and safety hazards. Microscale Chemistry Activities list and instructions. Home Practicals Home Ed version of Edexcel Scheme of Work - Edexcel produce a wonderful, but huge, scheme of work which covers the whole IGCSE Chemistry syllabus. For every topic it has textbook references and suggested demonstrations and class practicals. This version has been edited to add notes on which practicals one home-ed family has carried out, and further resources. Acid - Alkali Titration Neutralising Acids - Titration to compare indigestion remedies You don't need a burette to do this; a pipette or syringe will do the job. Indicators can be bought easily online (see Suppliers). The Illustrated Guide to Home Chemistry Experiments has instructions for a home titration on p205 with substitution advice if you do not have a burette. Flame Tests for Metals These can be done fairly easily at home, using a gas hob or large lighter as a flame source. Steve Spangler Science on flame tests RSC advice on flame tests for metals in the UK. Generating and Testing Gases Testing for Oxygen Oxygen re-ignites a glowing splint. A “glowing splint” is just a stick like a wooden kebab skewer that you have set alight and then blown out. When you are decomposing your hydrogen peroxide, you want to catch some oxygen and then test it. If you have made “elephant toothpaste” by putting washing-up liquid in your hydrogen peroxide before adding the catalyst, as above, then the bubbles will contain a lot of oxygen. However, the skin of the bubbles is made of water and detergent, and as we all know, poking a glowing stick into bubbles will extinguish the glow. But not necessarily with these -play around poking the glowing splint gently into the **upper part** of the foam, and see if the glow increases. Next, repeat the experiment without adding washing-up liquid, and try putting the glowing splint down into the container, just above the liquid. Don’t put the splint into the liquid. If all goes well and oxygen is being produced, you’ll see the splint re-ignite. Hydrogen We generated hydrogen at home by adding hydrochloric acid to powdered zinc. However, it is easy to do using more readily available materials if you don’t want to buy in chemistry stock. You can make it by adding aluminium foil to caustic soda solution (sodium hydroxide). Sodium hydroxide is caustic so you need gloves, goggles, covered skin etc.. When you make up the solution, put the water in first and then add the sodium hydroxide. This is because you get an exothermic reaction between sodium hydroxide and water; if you put the sodium hydroxide in first and then add water, the heat of the initial reaction could cause steam and bubbling and splashing. Putting the water in first and then adding the sodium hydroxide reduces the splash risk. Add aluminium foil when the caustic soda is all dissolved. After a little while, the reaction will get going and hydrogen will be produced. The container will still get hot, so you may wish to stand it in a bowl of cold water. See this YouTube video on generating hydrogen with caustic soda and aluminium foil. Using Hydrochloric acid and zinc: We found that just a large pinch of zinc powder in a test tube with 2mls of 4M Hydrochloric Acid produced enough hydrogen for us to do several tests. You are using acid so obviously, goggles and gloves on, feet and arms covered. Put the zinc in the test tube, then drop the acid onto it. Testing for hydrogen When you see bubbles rising, that is hydrogen. To test for the presence of hydrogen, it helps to have a partner. Put your thumb over the test tube and keep a firm seal until you feel pressure building up. Meanwhile, your partner lights the splint (wooden kebab skewer) and holds it up. We found it worked best to test as follows. The lighted splint is held still and the person with the test tube brings the tube up underneath it. Hydrogen is lighter than air so as soon as you remove your thumb, it floats up out of the tube. If the tube is directly under the flame, as close as possible, you have more chance of success. When the hydrogen meets the flame it makes a distinctive “Pop” sound which has a squeak to it. Here’s a lower-risk way of generating hydrogen, making bubbles with the gas - requires a side-arm test-tube,, still using caustic soda. Or you could combine it with some electrochemistry and use simply a battery and salt water; you won’t get much this way, but if you’re careful it will still be enough to test. Hydrogen Balloon I generated more hydrogen in a conical flask, but you could use a bottle as per the YouTube video on generating hydrogen with caustic soda and aluminium foil. I held a balloon over the neck of the flask until it was inflated a bit, then tied off the balloon and taped it to a long stick. Then I put a candle outside and took the balloon to the flame. A gratifying bang was heard and nice flames were seen. Testing for Carbon Dioxide How to make Limewater - to test for CO2. Easy home-make solution of calcium hydroxide. And here is a video showing how to test for CO2 in exhaled air compared to room air, using the limewater. Catalysis in biology From Futurelearn Kitchen Chemistry course. For this experiment you will need: * A potato * Yeast (dried or fresh) * Hydrogen peroxide (available at different concentrations - max 40% - at pharmacies) * A small amount of water * A few drops of washing-up liquid * A glass, jar, yoghurt pot or other container * Safety spectacles Please be aware that hydrogen peroxide is a bleach and will discolour any material it comes into contact with (even your hands). While it is always a good idea to wear safety spectacles when doing chemistry this is one experiment, depending on how it is carried out, where it is highly advisable. Mix the yeast and water and leave it to stand for 5 - 10 min. There should be enough water that the mixture pours easily. While you are waiting cut a fresh piece of potato. Put some hydrogen peroxide solution in a container and add the freshly cut piece of potato. What do you observe? Put some more hydrogen peroxide into another container and add a few drops of washing-up liquid. The enzymes in the yeast should turn the hydrogen peroxide into water and oxygen. As oxygen is a gas the washing up liquid will make a foam that captures the bubbles of the gas, making it easier to see what is happening. Add the yeast to the mixture of hydrogen peroxide and washing up liquid and observe what happens. Where to get chemicals and equipment You can buy small quantities of most of the chemicals you need on eBay or Amazon. Kitchen-Chemistry is an eBay store which works with many home educators, and the Echo Education distance learning tutors, to supply small quantities of chemicals and equipment used in IGCSE-level practicals. Email kitchenchemistry@btinternet.com For larger quantities see www.reagent.co.uk. Many chemicals can be supplied without restrictions, but if you need something which they say is ‘restricted’ then you can contact them and provide evidence that you’re working towards and exam. This company asked me to send some evidence that we were working towards a specification. Some things can be found easily in hardware stores, eg Sodium Hydroxide is Caustic Soda - NaOH. An easy source of hydrochloric acid is ‘Spirits of Salts’ which is sold in hardware/cleaning shops - it’s approx 30% HCl solution in water. Bunsen Burners For gentle heating, you can use a spirit burner or even a candle. However, some activities require intense, focused head and for this a bunsen burner or similar is helpful. A blow torch does exactly the same job as a bunsen burner, and if you get one with a stand then it can be used in the same way. However, the flame is not usually as easy to control as that on a bunsen. It is useful to have practice with a genuine bunsen burner so that you are confident using them safely. There are some options for home use which use LPG gas canisters, ie camping gas. Bunsen attached directly to canister. An advantage of this is no trailing hose, and it's easy to get the connection just right. Convenient and easy to use, but expensive. The model in the photo costs £35 approx from Better Equipped, including canister. LPG Bunsen attached to gas bottle by hose. This is the cheapest option - often available on eBay for under £10 and you can attach it to a camping gas cylinder. You need to get the correct regulator for the type of gas bottle you have - your gas cylinder supplier can usually provide these. If you already have a gas camping stove which uses a regulator, you can use the same bottle and regulator for the bunsen. One disadvantage is that you have to be careful of the trailing hose, but on the other hand that is more like a regular laboratory burner. You have to ensure the connections are made very tightly. Model in the photo costs around £5, but unless you already have a gas cylinder and regulator, these will cost far more than the burner! Balance A good, laboratory-style balance opens up the possibilities of experiments you can do. A 'balance' is just laboratory-speak for scales, but ordinary kitchen scales are not accurate enough to do many of the activities on the chemistry syllabus . If you're going to buy a new balance, preferably get one which will weigh in increments of 0.01g for IGCSE-level chemistry. A 'jeweller's scale' can be bought for under £10 and, according to this RSC Chemistry teachers' forum discussion, is robust enough for classroom use. A larger option is the My Weigh iBalance 201 which costs around £70 - eg http://www.ourweigh.co.uk/table-top-scales/ibalance-201.html . Rapidonline are brilliant for cheap equipment and have various robust-looking balances aimed at schools which weigh in intervals of 0.1g for around £35 + VAT. The full range is at http://www.rapidonline.com/pocket-portable-balances , then click 'parametric search' to make sense of it all. Rapidonline are brilliant for value and speed and service, but their website isn't the most user-friendly. Resources ‘Illustrated Guide to Home Chemistry Experiments’ by Robert Bruce Thompson. Book aimed at home-educators and those interested in doing serious home chemistry, but pitched at roughly A-level standard. Useful on safety and practical considerations when carrying out experiments at home, plus which pieces of equipment you can substitute or improvise. Author’s website, with some amendments and additions to the text. Support forums have lots of discussion from home-edders. The full text is available free online with the author's permission. I contacted the author to confirm this. He replied: "I have no objection to the books being posted on-line. My publisher, O'Reilly & Associates, and I are both big supporters of free/open-source software and the Creative Commons. In fact, all of my books have been published under a CC license that allows sharing...Of course, we want to make a living, but my wife's and my primary concern is that students be exposed to real hands-on science." Jim Clark, author of the Edexcel textbook, has a chapter-by-chapter list of additional resources here. http://www.chemguide.co.uk/igcse/index.html Practical Chemistry - http://www.practicalchemistry.org - thorough notes on safety issues etc.. so may help you to decide whether it’s practical to do this experiment at home. Also has good explanations and teaching tips. RSC Classic Chemistry Experiments - Royal Society of Chemistry. Source for any activities referred to as ‘CCE’ or ‘RSC CCE’ below. NOTE: Always worth checking the Practical Chemistry page on the CCE; often there are additional tips or updates. RSC Classic Chemistry Demonstrations - activities listed below as ‘RSC CC Demo’ are for the teacher to demonstrate, not for the class to do. These too are detailed on the RSC site; just go to RSC Learn Chemistry site and search for the demonstration you need, with title as listed in the Scheme of Work. RSC Education Playlist on Youtube RSC Demonstration Videos - for teachers, with demo tips: RSC/Teachers TV Video Clips: http://www.rsc.org/Education/Teachers/Resources/Practical-Chemistry/video-clips/index.asp Doc Brown’s free support page for IGCSE Edexcel Chemistry: Khan Academy - lots of chemistry videos. Basic chem lab techniques from About.com MIT Chemistry Lab Techniques - YouTube collection How to write a lab report: http://chemistry.about.com/od/chemistrylabexperiments/a/labreports.htm (I think this goes way beyond GCSE level though) Acid-Base titration step by step from titrations.info Chemistry lab technique tutorials: http://www.sciencebuddies.org/science-fair-projects/project_ideas/Chem_Lab_Techniques.shtml Safety issues: http://www.sciencebuddies.org/science-fair-projects/project_ideas/Chem_Safety.shtml Chemistry Diagrams: http://www.btinternet.com/~chemistry.diagrams/index.htm Home-ed High School Chemistry - a US-based list of resources and their chemistry curriculum, with good links.